CHECKING FOR GAUGE
The first brick on every new course (the ‘quoin brick’) must be checked and adjusted for gauge, where gauge is the vertical measure applied to the height of brickwork in terms of the combined thickness of bricks and the mortar bed joints between courses. All bed joints should be of regular thickness throughout the height of a wall – 10mm thick with an accepted industrial tolerance of + or -5 mm in any 3.0m height.
Bricklayers will usually check gauge by measuring with a tape, in multiples of the thickness of a course of bricks (65mm brick + 10mm bed joint = 75mm gauge). Typically, they will check that every fourth course measures 300mm. Specialist bricklayer’s measuring tapes are available, marked out for the purpose of gauging brickwork.
A more traditional alternative is a timber gauge lath marked with 75mm graduations. The gauge lath is made from a length of timber 50mm x 20mm in section (or similar), with the 75mm graduations marked on with permanent, shallow saw cuts. Adjusting a brick to gauge is achieved by simply tapping the brick down with the outside edge of the blade until a 10mm bed joint is reached. When tapping the brick down, cultivating a good eye for keeping the brick as horizontal as possible will make subsequent levelling easier.